Hydra

Table of Content

Hydra#

Hydra is an open-source Python framework that simplifies the development of research and other complex applications. The key feature is the ability to dynamically create a hierarchical configuration by composition and override it through config files and the command line.

Demo#

Load config from yaml file
Convert yaml config to typed object using dataclass
Override yaml data from CLI

config.yaml

db:
  driver: mysql
  table: bar
  user: bar
  password: foo

map yaml file to typed object using dataclass

@dataclass
class DB:
    driver: str
    table: str
    user: str
    password: str


@dataclass
class Settings:
    db: DB


cs = ConfigStore.instance()
# name `base_config` is used for matching it with the main.yaml's default section
cs.store(name="base_config", node=Settings)

full example

import cv2
import hydra
# from omegaconf import DictConfig, OmegaConf
from hydra.core.config_store import ConfigStore
from dataclasses import dataclass


@dataclass
class DB:
    driver: str
    table: str
    user: str
    password: str


@dataclass
class Settings:
    db: DB


cs = ConfigStore.instance()
# name `base_config` is used for matching it with the main.yaml's default section
cs.store(name="base_config", node=Settings)


@hydra.main(config_path=".", config_name="config", version_base="1.1")
def my_app(cfg: Settings) -> None:
    # print(OmegaConf.to_yaml(cfg))
    print(cfg)
    print(type(cfg))
    print(cfg.db.driver)
    print(cfg.db.table)

if __name__ == "__main__":
    my_app()